Multivariate analysis of risks for postoperative morbidity and mortality.

Preop: pre-operative; POD1: post-operative day 1.Multivariate logistic regression model adjusted with age, sex, preoperative hemoglobin levels, and BMI.N.A.: Because all in-hospital mortality (100%) occurred in the subgroup of patients with POD1 levels ≤ 2.7 g/dL (none in the subgroup with POD1 levels >2.7 g/dL), the odd ratio becomes infinity and can’t be accurately estimated by logistic regression model.*P